The invention relates to a particle beam accelerator for generating an electrically charged particle beam.
With such accelerators, particles of a predetermined charge and mass are extracted from a reservoir and supplied to an acceleration chamber formed between two different electrical potentials to finally provide a beam for use in further treatment procedures.
Patent DP 38 34 402 discloses a process in which the magnetically self-focussed electron beam or a pseudo-spark discharge is received at the anode exit of an electrically insulating quartz tube and is transported therein over a certain distance. A slight curvature or the tube has no noticeable effect on the beam transport and accordingly facilitates the search for the most suitable impact angle of the beam onto the target. To a certain degree, the tube protects the pseudo-spark chamber from ablation vapors and permits differential pumping because of the small pump cross-section. The generation or the electron beam with the technically complicated pseudo-spark chamber however is limited with regard to beam strength and divergence.
It is the object of the invention to achieve high particle beam intensities or equivalent thereto a high current, that is, a high current density, and a sharp focussing of the particle beam by economically acceptable means and expenditures.